Begin by attaching a straight bar to the lat pulldown machine and then adjust the knee pads so your legs will fit underneath of them comfortably; if you do not have a straight bar you can also use a wide grip bar. Sit down facing the machine and make sure that your feet are planted flat on the floor with your knees under the pads. Reach up and grab the bar with a grip that is slightly narrower than shoulder width with your palms facing your body. Lean back slightly and then pull the bar down towards your chest. Do not move your torso during the movement, and control the weight the entire time. Continue to pull the bar and squeeze your shoulder blades together until the bar nearly touches your chest. Pause slightly and then return the bar to the starting position.